mfyvie, you've done it!

I simply added the killspiders code you've mentioned at the top of the 'onlineusers.php' file and hey-presto it works perfect. I'm not sure where this setting is supposed to be set, but for the time being untill I find out where, everything works perfect. Although just to clarify I hope this doesn't prevent spiders from crawling my site and indexing it, I just want to remove spiders from the online users count.
Many thanks
mfyvie!